The objectives of the proposed research are to determine how hormone factors control fetal development. We plan to study the biosynthesis of fetal pituitary peptides related to ACTH and betaLPH to discover how their synthesis is controlled throughout gestation. New methods of extraction and purification of peptides by reversed phase high pressure liquid chromatogrophy will be used in a search for peptides which can control the growth of the fetal adrenal and the formation of corticosteroids and androgens. The control of biosynthesis of corticosteroids and androgens will be studied by the addition of peptides to fetal calf adrenal cells obtained at various stages of gestation. The mechanism whereby these peptides stimulate steroid genesis will be studied by investigating the binding of 125I labeled peptides to membrane receptors and by investigating both alpha and beta receptors on the fetal adrenal. We will also study the biosynthesis and metabolism of prostaglandins (PG) and thromboxanes (TX) in fetal calf hepatocytes and will measure the formation of PGE2, PGF2alpha, 6-oxoPGF1alpha and TXB2 from arachidonic acid. In addition we will examine the role of PGs in the formation of fetal hemoglobin. The role of estradiol in platelet aggregation will be examined by determining how it influences the formation of PGE2, PGF2alpha, and TXB2 in rabbit aorta. The role of insulin in fetal lung development in the rat will be studied. We will examine the 125I insulin binding to lung membrane receptors in the fetuses of diabetic rats and determine the effect of glucocorticoids on this binding and vice versa.